Transformer problem Dumble 50

[Oddvar R]

Hi. Any advice on transformer for the dumble 50w (022814715PP7D). I have use transformers from Weber, but they have gone twice. Could I use this?: https://www.tube-town.net/info/datenbla ... o50-pw.pdf

I have many amps with Hammond, so I would like to try something else?

[Guy77]

Hi. It will work. Just your B+ will be a little higher than stock on your power tubes. You may need to change the values in your dropping string a bit to get stock voltages on your preamp. I built a 50 watt ODS with a 200ma transformer (Hammond) and it has been running fine for the last 9yrs.

Cheers

Guy

[Oddvar R]

Thanks Guy.

[Guitarman18]

Hi,

I believe at one point (possibly still) inmadout https://www.inmadout.com/contact.asp made/makes transformers for tubetown.

I custom ordered one directly, with spec’d voltages and was really pleasantly surprised at how good and accurate the voltages were. It made the build a dream amp.

Good luck with your build.

[erwin_ve]

Oddvar, what about this one: https://www.tube-town.net/ttstore/netzt ... -watt.html
Its a good PT, has the right voltages, relay power winding.

Erwin

[Stephen1966]

Oddvar, what about this one: https://www.tube-town.net/ttstore/netzt ... -watt.html
Its a good PT, has the right voltages, relay power winding.

Erwin

I'm using the 100W versions of the TT output and power transformers and I did some testing on them in this post https://ampgarage.com/forum/viewtopic.php?f=6&t=35961. Not the best test results, but blame the experimenter and the equipment. You can see how I incorporated it in this post with some voltage data around page 20 https://ampgarage.com/forum/viewtopic.php?f=4&t=35724

Both transformers are now up and running and everything checks out okay. I thought the extra winding for the relays might end up being problematic with switching noise from the PT but it's dead quiet. They both run cool and have plenty of punch. I would recommend you try them.

[Oddvar R]

Oddvar, what about this one: https://www.tube-town.net/ttstore/netzt ... -watt.html
Its a good PT, has the right voltages, relay power winding.

Erwin

Good point, thanks...

[sergio]

Bassman PT / OT for a 50w

[VolkerStaub]

Sorry to hijack this thread, but could I use this PT for a SSS build?
Someone selling it locally, claiming it's from his Silverface Twin Reverb from the 70ies.

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[erwin_ve]

Sorry to hijack this thread, but could I use this PT for a SSS build?

In the original Sss002 is a 022756 PT.
The model you showed in the pic is the export version for 220/240v, so yes.
Btw I'll ship your chassis and pcb tomorrow.

Best,

Erwin

[VolkerStaub]

In the original Sss002 is a 022756 PT.
The model you showed in the pic is the export version for 220/240v, so yes.
Btw I'll ship your chassis and pcb tomorrow.

So export means only it's dedicated for the European market. I see.
Using this over the Hammond 290FEX requires no changes whatsoever?

P.S. really looking forward for the PCBs and enclosure Thanks!

[erwin_ve]

In the original Sss002 is a 022756 PT.
The model you showed in the pic is the export version for 220/240v, so yes.
Btw I'll ship your chassis and pcb tomorrow.

So export means only it's dedicated for the European market. I see.
Using this over the Hammond 290FEX requires no changes whatsoever?

P.S. really looking forward for the PCBs and enclosure Thanks!

Export version is basically world domination for all voltages incl EU.

[Oddvar R]

A little update on my transformer issue. At first I had a W022798 Transformer 40w OT and a Hammond 1750M PT. The Weber PT wnt dead twice, so I decided to try something else. The ywo mentioned transformers sounded very good, a very sweet overdrive.

I bought the Dumble 50w offering from Tube Town, but well installed, the overdrive doesn't work as sweet as before, there is a distinct difference. Much cleaner soundg, even at full volume.

So I wonder if I should revert to a smaller combo transformer, 50w to 40 watt? Any views on this?

[Roe]

A little update on my transformer issue. At first I had a W022798 Transformer 40w OT and a Hammond 1750M PT. The Weber PT wnt dead twice, so I decided to try something else. The ywo mentioned transformers sounded very good, a very sweet overdrive.

I bought the Dumble 50w offering from Tube Town, but well installed, the overdrive doesn't work as sweet as before, there is a distinct difference. Much cleaner soundg, even at full volume.

So I wonder if I should revert to a smaller combo transformer, 50w to 40 watt? Any views on this?

many weber PTs have gone bad if used with 50hz, not 60hz. After they became aware of the issue, weber claimed that they improved the export transformers so that they don't overheat. I've personally had 3 PTs with this problem and two of them blew (a fourth one does not suffer from this problem at all)

[martin manning]

I bought the Dumble 50w offering from Tube Town, but well installed, the overdrive doesn't work as sweet as before, there is a distinct difference. Much cleaner soundg, even at full volume.

So I wonder if I should revert to a smaller combo transformer, 50w to 40 watt? Any views on this?

It’s not clear but is this the OT you are referring to? If so, switch back to the smaller one and see if it sounds better as you remember. Unless you are in the habit of playing it at full volume, I don’t think the lower power rating will be an issue.